[Parser] Parse if-else in the new wat parser and IRBuilder (#5963)

Parse both the straight-line and folded versions of if, including the
abbreviations that allow omitting the else clause. In the IRBuilder, generalize
the scope stack to be able to track scopes other than blocks and add methods for
visiting the beginnings of ifs and elses.

1 files changed, 373 insertions, 13 deletions

diff --git a/test/lit/wat-kitchen-sink.wast b/test/lit/wat-kitchen-sink.wast
index 3b42db434..375b8c993 100644
--- a/test/lit/wat-kitchen-sink.wast
+++ b/test/lit/wat-kitchen-sink.wast
@@ -5,18 +5,18 @@
 (module $parse
  ;; types
 
+ ;; CHECK:      (type $void (sub (func)))
+
  ;; CHECK:      (type $ret2 (func (result i32 i32)))
  (type $ret2 (func (result i32 i32)))
 
  (rec
-  ;; CHECK:      (type $void (sub (func)))
+  ;; CHECK:      (type $2 (func (result i32)))
 
   ;; CHECK:      (type $pair (struct (field (mut i32)) (field (mut i64))))
 
   ;; CHECK:      (type $a1 (array i64))
 
-  ;; CHECK:      (type $4 (func (result i32)))
-
   ;; CHECK:      (type $5 (func (param i32 i64)))
 
   ;; CHECK:      (type $a2 (array (mut f32)))
@@ -233,7 +233,7 @@
  ;; CHECK:      (func $f2 (type $8) (param $x i32)
  ;; CHECK-NEXT: )
  (func $f2 (param $x i32))
- ;; CHECK:      (func $f3 (type $4) (result i32)
+ ;; CHECK:      (func $f3 (type $2) (result i32)
  ;; CHECK-NEXT:  (i32.const 0)
  ;; CHECK-NEXT: )
  (func $f3 (result i32)
@@ -307,7 +307,7 @@
   nop
  )
 
- ;; CHECK:      (func $add (type $4) (result i32)
+ ;; CHECK:      (func $add (type $2) (result i32)
  ;; CHECK-NEXT:  (i32.add
  ;; CHECK-NEXT:   (i32.const 1)
  ;; CHECK-NEXT:   (i32.const 2)
@@ -319,7 +319,7 @@
   i32.add
  )
 
- ;; CHECK:      (func $add-folded (type $4) (result i32)
+ ;; CHECK:      (func $add-folded (type $2) (result i32)
  ;; CHECK-NEXT:  (i32.add
  ;; CHECK-NEXT:   (i32.const 1)
  ;; CHECK-NEXT:   (i32.const 2)
@@ -332,7 +332,7 @@
   )
  )
 
- ;; CHECK:      (func $add-stacky (type $4) (result i32)
+ ;; CHECK:      (func $add-stacky (type $2) (result i32)
  ;; CHECK-NEXT:  (local $scratch i32)
  ;; CHECK-NEXT:  (i32.add
  ;; CHECK-NEXT:   (block (result i32)
@@ -352,7 +352,7 @@
   i32.add
  )
 
- ;; CHECK:      (func $add-stacky-2 (type $4) (result i32)
+ ;; CHECK:      (func $add-stacky-2 (type $2) (result i32)
  ;; CHECK-NEXT:  (local $scratch i32)
  ;; CHECK-NEXT:  (i32.add
  ;; CHECK-NEXT:   (i32.const 1)
@@ -372,7 +372,7 @@
   i32.add
  )
 
- ;; CHECK:      (func $add-stacky-3 (type $4) (result i32)
+ ;; CHECK:      (func $add-stacky-3 (type $2) (result i32)
  ;; CHECK-NEXT:  (local $scratch i32)
  ;; CHECK-NEXT:  (local.set $scratch
  ;; CHECK-NEXT:   (i32.add
@@ -390,7 +390,7 @@
   nop
  )
 
- ;; CHECK:      (func $add-stacky-4 (type $4) (result i32)
+ ;; CHECK:      (func $add-stacky-4 (type $2) (result i32)
  ;; CHECK-NEXT:  (local $scratch i32)
  ;; CHECK-NEXT:  (local $scratch_1 i32)
  ;; CHECK-NEXT:  (local $scratch_2 i32)
@@ -424,7 +424,7 @@
   nop
  )
 
- ;; CHECK:      (func $add-unreachable (type $4) (result i32)
+ ;; CHECK:      (func $add-unreachable (type $2) (result i32)
  ;; CHECK-NEXT:  (i32.add
  ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:   (i32.const 1)
@@ -436,7 +436,7 @@
   i32.add
  )
 
- ;; CHECK:      (func $add-unreachable-2 (type $4) (result i32)
+ ;; CHECK:      (func $add-unreachable-2 (type $2) (result i32)
  ;; CHECK-NEXT:  (drop
  ;; CHECK-NEXT:   (i32.const 1)
  ;; CHECK-NEXT:  )
@@ -451,7 +451,7 @@
   i32.add
  )
 
- ;; CHECK:      (func $add-unreachable-3 (type $4) (result i32)
+ ;; CHECK:      (func $add-unreachable-3 (type $2) (result i32)
  ;; CHECK-NEXT:  (drop
  ;; CHECK-NEXT:   (i32.const 1)
  ;; CHECK-NEXT:  )
@@ -810,6 +810,366 @@
   nop
  )
 
+ ;; CHECK:      (func $if-else (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else
+  i32.const 0
+  if
+   nop
+  else
+   nop
+  end
+ )
+
+ ;; CHECK:      (func $if-else-empty (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-empty
+  i32.const 0
+  if
+  else
+  end
+ )
+
+ ;; CHECK:      (func $if-else-many (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (block
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (block
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-many
+  i32.const 0
+  if
+   nop
+   nop
+  else
+   nop
+   nop
+  end
+ )
+
+ ;; CHECK:      (func $if-else-single-nested (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (f32.const 1)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (f64.const 2)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-single-nested
+  i32.const 0
+  if
+   f32.const 1
+   drop
+  else
+   f64.const 2
+   drop
+  end
+ )
+
+ ;; CHECK:      (func $if-else-labeled (type $void)
+ ;; CHECK-NEXT:  (block $l
+ ;; CHECK-NEXT:   (if
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-labeled
+  i32.const 0
+  if $l
+   nop
+  else $l
+   nop
+  end $l
+ )
+
+ ;; CHECK:      (func $if-no-else (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-no-else
+  i32.const 0
+  if
+   nop
+  end
+ )
+
+ ;; CHECK:      (func $if-else-result (type $2) (result i32)
+ ;; CHECK-NEXT:  (if (result i32)
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (i32.const 1)
+ ;; CHECK-NEXT:   (i32.const 2)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-result (result i32)
+  i32.const 0
+  if (result i32)
+   i32.const 1
+  else
+   i32.const 2
+  end
+ )
+
+ ;; CHECK:      (func $if-else-labeled-result (type $2) (result i32)
+ ;; CHECK-NEXT:  (block $l (result i32)
+ ;; CHECK-NEXT:   (if (result i32)
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:    (i32.const 1)
+ ;; CHECK-NEXT:    (i32.const 2)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-labeled-result (result i32)
+  i32.const 0
+  if $l (result i32)
+   i32.const 1
+  else
+   i32.const 2
+  end
+ )
+
+ ;; CHECK:      (func $if-else-folded (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded
+  (if
+   (i32.const 0)
+   (then
+    nop
+   )
+   (else
+    nop
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-else-folded-empty (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded-empty
+  (if
+   (i32.const 0)
+   (then)
+   (else)
+  )
+ )
+
+ ;; CHECK:      (func $if-else-folded-many (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (block
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (block
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded-many
+  (if
+   (i32.const 0)
+   (then
+    nop
+    nop
+   )
+   (else
+    nop
+    nop
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-else-folded-single-nested (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.eqz
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 1)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 2)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded-single-nested
+  (if
+   (i32.eqz
+    (i32.const 0)
+   )
+   (then
+    (drop
+     (i32.const 1)
+    )
+   )
+   (else
+    (drop
+     (i32.const 2)
+    )
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-else-folded-labeled (type $void)
+ ;; CHECK-NEXT:  (block $l
+ ;; CHECK-NEXT:   (if
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:    (nop)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded-labeled
+  (if $l
+   (i32.const 0)
+   (then
+    nop
+   )
+   (else
+    nop
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-no-else-folded (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (nop)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-no-else-folded
+  (if
+   (i32.const 0)
+   (then
+    nop
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-else-folded-result (type $2) (result i32)
+ ;; CHECK-NEXT:  (if (result i32)
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:   (i32.const 1)
+ ;; CHECK-NEXT:   (i32.const 2)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded-result (result i32)
+  (if (result i32)
+   (i32.const 0)
+   (then
+    i32.const 1
+   )
+   (else
+    i32.const 2
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-else-folded-labeled-result (type $2) (result i32)
+ ;; CHECK-NEXT:  (block $l (result i32)
+ ;; CHECK-NEXT:   (if (result i32)
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:    (i32.const 1)
+ ;; CHECK-NEXT:    (i32.const 2)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-folded-labeled-result (result i32)
+  (if $l (result i32)
+   (i32.const 0)
+   (then
+    i32.const 1
+   )
+   (else
+    i32.const 2
+   )
+  )
+ )
+
+ ;; CHECK:      (func $if-else-mixed (type $void)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (if (result i32)
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:    (i32.const 1)
+ ;; CHECK-NEXT:    (i32.const 2)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (if
+ ;; CHECK-NEXT:    (if (result i32)
+ ;; CHECK-NEXT:     (i32.const 3)
+ ;; CHECK-NEXT:     (i32.const 4)
+ ;; CHECK-NEXT:     (i32.const 5)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:    (if
+ ;; CHECK-NEXT:     (i32.const 6)
+ ;; CHECK-NEXT:     (drop
+ ;; CHECK-NEXT:      (i32.const 7)
+ ;; CHECK-NEXT:     )
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $if-else-mixed
+  i32.const 0
+  if (result i32)
+   i32.const 1
+  else
+   i32.const 2
+  end
+  if
+   (if
+    (if (result i32)
+     (i32.const 3)
+     (then
+      (i32.const 4)
+     )
+     (else
+      (i32.const 5)
+     )
+    )
+    (then
+     i32.const 6
+     if
+      i32.const 7
+      drop
+     end
+    )
+   )
+  end
+ )
+
  ;; CHECK:      (func $multivalue-nested (type $ret2) (result i32 i32)
  ;; CHECK-NEXT:  (local $scratch (i32 i32))
  ;; CHECK-NEXT:  (block (result i32 i32)